The present invention pertains to a cleaner. More specifically, the present invention pertains to a non-flammable ternary cleaning solvent for use in precision cleaning applications.
Cleaning solvents or cleaners are used during the manufacture and rework of electronic, telecommunications and other electrical equipment to clean the components prior to final assembly. These cleaners are also used during maintenance operations carried out on electrical equipment in order to provide for proper electrical conductivity where two conductive (e.g., metal) surfaces are to be joined to one another in electrical contact.
For example, these cleaners are used during the manufacture, maintenance, repair and assembly of printed circuit boards, connectors, relays and contacts, solenoids, motors and motor windings, circuit breakers, circuit breaker panels, transformers, electrical and data communication connectors and switching devices, electronic controls, timers, cable assemblies, splices and terminations, hydraulic and pneumatic equipment, magnetic read/write equipment, optical equipment and the like.
Typically, these cleaners are used to remove contaminants, and more particularly, flux, grease, light oils, corrosive contaminants, oxidation products and the like prior to a final assembly or during or after equipment and component maintenance.
Many such cleaners are provided in aerosol form. These aerosol cleaners include a solvent and a propellant. Many aerosol formulations contain constituents that render the formulation relatively flammable. That is, the solvents, in and of them selves (without the propellant) are relatively flammable. This can be problematic in a manufacturing facility, as during fabrication or in a workplace when performing equipment and component maintenance. Moreover, many of these aggressive solvents cannot be used with certain types of plastics due to their aggressive nature. Nevertheless, because of the strong or aggressive cleaning characteristics of these formulations, for many applications their use continues.
Other formulations are known that exhibit lower flammability tendencies. However, these formulations typically do not have sufficiently aggressive cleaning characteristics, and as such are not of great import or use. Moreover many of the aforementioned cleaners (solvents) are not dual application use. That is, many of these formulations can be used either as a liquid or as an aerosol, but not necessarily as both.
Accordingly, there exists a need for a cleaning solvent having good cleaning characteristics, as well as low flammability. Desirably, such a solvent has low or no ozone depletion potential and a high degree of plastic compatibility. More desirably, such a cleaner is formulated so that it can be used as a liquid or, with the proper propellant, as an aerosol.
A nonflammable ternary liquid cleaner is formulated from first, second and third solvents. The first solvent is a hydrofluorocarbon, the second solvent is a dichloroethylene and the third solvent is a hydrochlorofluorocarbon. The hydrochlorofluorocarbon imparts low flammability to the cleaner.
The first solvent, hydrofluorocarbon, is present in a concentration of at about 10 percent to about 80 percent by weight of the cleaner, the second solvent, the dichloroethylene, is present in a concentration of about 10 percent to about 60 percent by weight of the cleaner and the third solvent, the hydrochlorofluorocarbon is present in a concentration of at about 10 percent to about 40 percent by weight of the cleaner. The cleaner exhibits low to no residual flammability.
In a present formulation, the first solvent is 1,1,1,3,3-pentafluorobutane, the second solvent is trans-1,2-dichloroethylene and the third solvent is 3,3-dichloro-1,1,1,2,2-pentafluoropropane and/or 1,3-dichloro-1,1,2,2,3-pentafluoropropane. In the present formulation, the third solvent is present in a concentration of about 12 percent to about 15 percent.
The cleaner can be used as a liquid. Alternately, the cleaner can be formulated as an aerosol and includes a propellant. A preferred propellant is present in a concentration of less than about 5 percent to about 30 percent of a total weight of the cleaner and the propellant. A preferred propellant is an HFC liquefied gas, such as tetrafluoroethane. A most preferred tetrafluoroethane is 1,1,1,2-tetrafluoroethane.
Other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.